Why cant I see SSDP protocol packets when using Wifi Monitor mode on Ubuntu

I'm looking to snoop on an SSDP conversation between two devices on Wifi. I've set up a WireShark instance on a Ubuntu machine and condifured a "Monitor" device using these instructions: https://sandilands.info/sgordon/capturing-wifi-in-monitor-mode-with-iw

However when I now capture via the mon0 device I only see 802.11 protocol and can'ts see any SSDP packets

I had tried just ticking the the "monitor" box on the interfaces list but it would not stay "ticked". The output of iw dev is:

Why cant I see SSDP protocol packets when using Wifi Monitor mode on Ubuntu

I'm looking to snoop on an SSDP conversation between two devices on Wifi. I've set up a WireShark instance on a Ubuntu machine and condifured a "Monitor" device using these instructions: https://sandilands.info/sgordon/capturing-wifi-in-monitor-mode-with-iw

However when I now capture via the mon0 device I only see 802.11 protocol packets and can'ts can't see any SSDP packets

I had tried just ticking the the "monitor" box on the interfaces list but it would not stay "ticked". The output of iw dev is:

Why cant I see SSDP protocol packets when using Wifi Monitor mode on Ubuntu

I'm looking to snoop on an SSDP conversation between two devices on Wifi. I've set up a WireShark instance on a Ubuntu machine and condifured configured a "Monitor" device using these instructions: https://sandilands.info/sgordon/capturing-wifi-in-monitor-mode-with-iw

However when I now capture via the mon0 device I only see 802.11 protocol packets and can't see any SSDP packets

I had tried just ticking the the "monitor" box on the interfaces list but it would not stay "ticked". The output of iw dev is: